Following the Quectel_GSM_TCPIP_Application_Note_V1.2.pdf manual, the “3.1. Single TCP or UDP connection as a client” example mentions the “AT+QISACK” command to query the acknowledged data.
In my case, the data is received on the server, but the “AT+QISACK” response is always the same:
+QISACK: 355, 0, 355
According to the manual, the server didn’t acknowledged the data.
How can the server signal that it acknowledged the data?